Microscope objectives

ABSTRACT

Microscope objectives having a numerical aperture of substantially 0.25 and a magnification of about 10X provide a substantially flat image field of about 24mm.

BACKGROUND OF THE INVENTION

This invention relates to microscope objectives and more particularly tomicroscope objectives which have a numerical aperture of substantially0.25, a magnification of substantially 10X and a substantially flatimage field of about 24mm. The microscope objectives of this inventionare well corrected for the usual chromatic image aberrations, as well asspherical aberration, coma and astigmatism. The substantially flat imagefield of about 24mm is provided when the objectives are used with aconventional 10X eyepiece and a microscope having a telescope objectiveas described in U.S. Pat. No. 3,355,234.

THE DRAWINGS

FIG. 1 is an optical diagram of one embodiment of the present invention;

FIG. 2 is an optical diagram of another embodiment of the presentinvention;

FIG. 3 is an optical diagram of a further embodiment of the presentinvention; and

FIG. 4 is an optical diagram of a still further embodiment of thepresent invention.

DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the objective XX is shown in a view transverse toits optical axis relative to object plane O and illustrate the lenselements aligned along the optical axis. The first element I of theobjective is a concavo-convex positive singlet followed by the secondlens element II, which is also a concavo-convex positive singlet. Thethird and final lens element III of the embodiment is a double convexpositive doublet. The parameters of the objective are set forth in TableI wherein the axial thicknesses of successive lens elements aredesignated T1 to T4, and the successive axial spaces from the objectplane (designated O) are S1 to S3. The successive lens radii aredesignated R1 to R7 wherein the minus sign (-) applies to surfaces whosecenter of curvature lies on the object side of their vertices. Therefractive indices and Abbe numbers of the glasses in the successivelenses are absolute values designated ND(1) to ND(4), and ν(1) to ν(4)respectively.

                                      TABLE I                                     __________________________________________________________________________                                    Refractive                                                                              Abbe                                Lens                                                                                Radius  Thickness                                                                              Space    Index     Number                              __________________________________________________________________________                           S.sub.1 = 0.201360F                                        R.sub.1 = -0.297233F                                                      I             T.sub.1 = 0.273567F                                                                             ND(1) = 1.78816                                                                         ν(1) = 47.37                         R.sub.2 = -0.449693F                                                                             S.sub.2 = 0.005471F                                        R.sub.3 = -2.09030F                                                       II            T.sub.2 = 0.164140F                                                                             ND(2) = 1.78816                                                                         ν(2) = 47.37                         R.sub.4 = -0.0780545F                                                                            S.sub.3 = 0.961457F                                        R.sub.5 = 113.3618F                                                                     T.sub.3 = 0.082070F                                                                             ND(3) = 1.80491                                                                         ν(3) = 25.42                     III R.sub.6 = 1.19907F                                                                      T.sub.4 = 0.191497F                                                                             ND(4) = 1.58304                                                                         ν(4) = 59.43                         R.sub.7 = -1.01792F                                                       __________________________________________________________________________

In the foregoing, as well as succeeding tables, F is the focal length ofthe objective in millimeters and all values are to be consideredvariable within normal manufacturing tolerances.

The optical values for a specific objective of this embodiment having afocal length of 18.277mm are:

                  TABLE II                                                        ______________________________________                                        Lens     Radius      Thickness   Space                                        ______________________________________                                                                         S.sub.1 = 3.680                                     R.sub.1 = -5.4325                                                      I                    T.sub.1 = 5.000                                                 R.sub.2 = -8.2190                                                                                       S.sub.2 = 0.100                                     R.sub.3 = -38.204                                                      II                   T.sub.2 = 3.000                                                 R.sub.4 = -14.266                                                                                       S.sub.3 = 17.573                                    R.sub.5 = 2071.914                                                                          T.sub.3 = 1.500                                          III    R.sub.6 = 21.915                                                                            T.sub.4 = 3.500                                                 R.sub.7 = -18.605                                                      ______________________________________                                    

Referring to FIG. 2, which is a preferred embodiment of the presentinvention, the first three elements, IV, V and VI of objective XXI havethe same type of curvature as the three elements shown in FIG. 1 forobjective XX. The fourth and final element of this embodiment is aconvex-concavo negative singlet. The parameters of this objective areset forth in Table III wherein the axial thicknesses of successive lenselements are designated T5 to T9 and the successive axial spaces fromthe object plane (designated O) are S4 to S7. The successive lens radiiare designated R8 to R16 where the minus sign (-) applies to surfaceswhose center of curvature lies on the object side of their vertices. Therefractive indices and Abbe numbers of the glasses in the successivelenses are absolute values designated ND(5) to ND(9), and ν(5) to ν(9)respectively.

                                      TABLE III                                   __________________________________________________________________________                                 Refractive                                                                              Abbe                                   Lens                                                                                Radius Thickness                                                                             Space   Index     Number                                 __________________________________________________________________________                         S.sub.4 = 0.3382F                                            R.sub.8 = -0.4274F                                                        IV           T.sub.5 = 0.2737F                                                                             ND(5) = 1.78833                                                                         ν(5) = 50.47                            R.sub.9 = -0.5552F                                                                             S.sub.5 = 0.0328F                                            R.sub.10 = -0.9581F                                                       V            T.sub.6 = 0.1642F                                                                             ND(6) = 1.78833                                                                         ν(6) = 50.47                            R.sub.11 = -0.7506F                                                                            S.sub.6 = 0.7957                                             R.sub.12 = 2.2095F                                                                     T.sub.7 = 0.0821F                                                                             ND(7) = 1.78446                                                                         ν(7) = 25.75                        VI  R.sub.13 = 0.7295F                                                                     T.sub.8 = 0.1916F                                                                             ND(8) = 1.69669                                                                         ν(8) = 56.13                            R.sub.14 = -2.6553F                                                                            S.sub.7 = 0.0049F                                            R.sub.15 = 0.5296F                                                        VII          T.sub.9 = 0.1916F                                                                             ND(9) = 1.69669                                                                         ν(9) = 56.13                            R.sub.16 = 0.4342F                                                        __________________________________________________________________________

The optical values for a specific objective of this embodiment having afocal length of 18.265 are:

                  TABLE IV                                                        ______________________________________                                        Lens     Radius      Thickness   Space                                        ______________________________________                                                                         S.sub.4 = 6.180                                     R.sub.8 = -7.807                                                       IV                   T.sub.5 = 5.000                                                 R.sub.9 = -10.140                                                                                       S.sub.5 = 0.600                                     R.sub.10 = -17.500                                                     V                    T.sub.6 = 3.000                                                 R.sub.11 = -13.710                                                                                      S.sub.6 = 14.534                                    R.sub.12 = 40.356                                                                           T.sub.7 = 1.500                                          VI     R.sub.13 = 13.325                                                                           T.sub.8 = 3.500                                                 R.sub.14 = -48.500                                                                                      S.sub.7 = 0.0900                                    R.sub.15 = 9.674                                                       VII                  T.sub.9 = 3.500                                                 R.sub.16 = 7.934                                                       ______________________________________                                    

Referring to FIG. 3, an objective XXII has a first element VIII, whichis a concavo-convex positive singlet, a second element IX, which is aconcavo-convex positive singlet, a third element X, which is a doubleconvex positive singlet and a fourth element XI, which is aconcavo-convex positive doublet. The parameters of this objective areset forth in Table V wherein the axial thicknesses of successive lenselements are designated T9 to T13, and the successive axial spaces fromthe object plane (designated O) are S8 to S11. The successive lens radiiare designated R17 to R25 where the minus sign (-) applies to surfaceswhose center of curvature lies on the object side of their vertices. Therefractive indices and Abbe numbers of the glasses in the successivelenses are absolute values designated ND(9) to ND(13), and ν(9) to ν(13)respectively.

                                      TABLE V                                     __________________________________________________________________________                                    Refractive                                                                              Abbe                                Lens                                                                                Radius  Thickness                                                                              Space    Index     Number                              __________________________________________________________________________                           S.sub.8  = 0.20151F                                        R.sub.17 = -0.27049F                                                      VIII          T.sub.9  = 0.27378F                                                                             ND(9) = 1.78816                                                                         ν(9) = 47.37                         R.sub.18 = -0.47856F                                                                             S.sub.9  = 0.00548F                                        R.sub.19 = -1.71598F                                                      IX            T.sub.10 = 0.16427F                                                                             ND(10) = 1.78816                                                                        ν(10) = 47.37                        R.sub.20 = -0.89799F                                                                             S.sub.10 = 0.25847F                                        R.sub.21 = 3.03510F                                                       X             T.sub.11 = 0.19164F                                                                             ND(11) = 1.78816                                                                        ν(11) = 47.37                        R.sub.22 = -7.39856F                                                                             S.sub.11 = 0.53892F                                        R.sub.23 = -4.65088F                                                                    T.sub.12 = 0.08213F                                                                             ND(12) = 1.80491                                                                        ν(12) = 25.42                    XI  R.sub.24 = 0.76274F                                                                     T.sub.13 = 0.19164F                                                                             ND(13) = 1.70166                                                                        ν(13) = 41.00                        R.sub.25 = -1.15457F                                                      __________________________________________________________________________

The optical values for a specific objective of this embodiment having afocal length of 18.263 are set forth in Table VI.

                  TABLE VI                                                        ______________________________________                                        Lens     Radius     Thickness   Space                                         ______________________________________                                                                        S.sub.8  = 3.680                                     R.sub.17 = -4.940                                                      VIII                T.sub.9  = 5.000                                                 R.sub.18 = -8.740                                                                                      S.sub.9  = 0.100                                     R.sub.19 = -13.339                                                     IX                  T.sub.10 = 3.000                                                 R.sub.20 = -16.400                                                                                     S.sub.10 = 4.720                                     R.sub.21 = 55.430                                                      X                   T.sub.11 = 3.500                                                 R.sub.22 = -135.120                                                                                    S.sub.11 = 9.842                                     R.sub.23 = -84.939                                                                         T.sub.12 = 1.500                                          XI     R.sub.24 = 13.930                                                                          T.sub.13 = 3.500                                                 R.sub.25 = -21.086                                                     ______________________________________                                    

Referring to FIG. 4, the objective XXIII has the first three elementsXII, XIII and XIV with the same type of curvature as the respectiveelements of objective XXII in FIG. 3. The fourth and final element XV isa double convex positive doublet. The parameters of this objective areset forth in Table VII wherein the axial thicknesses of successive lenselements are designated T14 to T18, and the successive axial spaces fromthe object plane (designated O) are S12 to S15. The successive lensradii are designated R26 to R34 where the minus sign (-) applies tosurfaces whose center of curvature lies on the object side of theirvertices. The refractive indices and Abbe numbers of the glasses in thesuccessive lenses are absolute values designated ND(14) to ND(18) andν(14) to ν(18) respectively.

                                      TABLE VII                                   __________________________________________________________________________                                    Refractive                                                                              Abbe                                Lens                                                                                Radius  Thickness                                                                              Space    Index     Number                              __________________________________________________________________________                           S.sub.12 = 0.40735F                                        R.sub.26 = -0.32605F                                                      XII           T.sub.14 = 0.26827F                                                                             ND(14) = 1.78816                                                                        ν(14) = 47.37                        R.sub.27 = -0.53042F                                                                             S.sub.13 = 0.00537F                                        R.sub.28 = -2.16525F                                                      XIII          T.sub.15 = 0.16096F                                                                             ND(15) = 1.78816                                                                        ν(15) = 47.37                        R.sub.29 = -0.99163F                                                                             S.sub.14 = 0.12438F                                        R.sub.30 = 1.73624F                                                       XIV           T.sub.16 = 0.18779F                                                                             ND(16) = 1.78816                                                                        ν(16) = 47.37                        R.sub.31 = -12.952F                                                                              S.sub.15 = 0.41384F                                        R.sub.32 = 12.952F                                                                      T.sub.17 = 0.08048F                                                                             ND(17) = 1.80491                                                                        ν(17) = 25.42                    XV  R.sub.33 = 0.79515F                                                                     T.sub.18 = 0.18779F                                                                             ND(18) = 1.52249                                                                        ν(18) = 60.13                        R.sub.34 = -1.4003F                                                       __________________________________________________________________________

The optical values for a specific objective of this embodiment having afocal length of 18.638mm are given in Table VIII.

                  TABLE VIII                                                      ______________________________________                                        Lens     Radius     Thickness   Space                                         ______________________________________                                                                        S.sub.12 = 7.592                                     R.sub.26 = -6.077                                                      XII                 T.sub.14 = 5.000                                                 R.sub.27 = -9.886                                                                                      S.sub.13 = 0.100                                     R.sub.28 = -40.356                                                     XIII                T.sub.15 = 3.000                                                 R.sub.29 = -18.482                                                                                     S.sub.14 = 2.318                                     R.sub.30 = 32.360                                                      XIV                 T.sub.16 = 3.500                                                 R.sub.31 = -241.400                                                                                    S.sub.15 = 7.713                                     R.sub.32 = 241.400                                                                         T.sub.17 = 1.500                                          XV     R.sub.33 = 14.820                                                                          T.sub.18 = 3.500                                                 R.sub.34 = -26.098                                                     ______________________________________                                    

The values in the foregoing tables may be adjusted to accommodate normalmanufacturing tolerances.

What is claimed is:
 1. A microscope objective having a numericalaperture of about 0.25 which comprises, in alignment from an objectplane along an optical axis,a concavo-convex positive singlet as a firstelement, a concavo-convex positive singlet as a second element, and apositive doublet as another element, said positive doublet being thesole doublet of said objective and having as the second componentthereof a double convex lens.
 2. The microscope objective of claim 1wherein said positive doublet is double convex and further including aconvex-concave negative singlet as a fourth element aligned along theoptical axis following the positive doublet.
 3. The microscope objectiveof claim 1 wherein said positive doublet is concavo-convex and furtherincluding a double convex positive singlet as a fourth element alignedalong the optical axis and being interposed between said second elementand said positive doublet.
 4. The microscope objective of claim 1wherein said positive doublet is double convex and further including adouble convex positive singlet as a fourth element aligned along theoptical axis and being interposed between said second element and saidpositive doublet.
 5. The microscope objective of claim 1 wherein saidpositive doublet is double convex and consisting of the defined lenselements having the following parameters:

    __________________________________________________________________________                                Refractive                                                                             Abbe                                     Lens                                                                                Radius                                                                              Thickness                                                                             Space   Index    Number                                   __________________________________________________________________________                        S.sub.1 = 0.201360F                                           R.sub.1 = -0.297233F                                                      I           T.sub.1 = 0.273567F                                                                           ND(1) = 1.78816                                                                        ν(1) = 47.37                              R.sub.2 = -0.449693F                                                                          S.sub.2 = 0.005471F                                           R.sub.3 = -2.09030F                                                       II          T.sub.2 = 0.164140F                                                                           ND(2) = 1.78816                                                                        ν(2) = 47.37                              R.sub.4 = -0.0780545F                                                                         S.sub.3 = 0.961457F                                           R.sub.5 = 113.3618F                                                                   T.sub.3 = 0.082070F                                                                           ND(3) = 1.80491                                                                        ν(3) = 25.42                          III R.sub.6 = 1.19907F                                                                    T.sub.4 = 0.191497F                                                                           ND(4) = 1.58304                                                                        ν(4) = 59.43                              R.sub.7 = -1.01792F                                                       __________________________________________________________________________     wherein axial thicknesses of successive lens elements are T1 to T4,     successive axial spaces are S1 to S3, successive lens radii are R1 to R7,     where the - applies to surfaces whose center or curvature lies on the     object side of the vartices, refractive indices and Abbe Numbers of the     successive lenses are ND(1) to ND(4), ν(1) to ν(4) respectively, and     F is the focal length of the objective in millimeters.


6. The microscope objective of claim 5 wherein F is 18.277mm.
 7. Themicroscope objective of claim 2 consisting of the defined lens elementshaving the following parameters:

    __________________________________________________________________________                                 Refractive                                                                              Abbe                                   Lens                                                                                Radius Thickness                                                                             Space   Index     Number                                 __________________________________________________________________________                         S.sub.4 = 0.3382F                                            R.sub.8 = -0.4274F                                                        IV           T.sub.5 = 0.2737F                                                                             ND(5) = 1.78833                                                                         ν(5) = 50.47                            R.sub.9 = -0.5552F                                                                             S.sub.5 = 0.0328F                                            R.sub.10 = -0.9581F                                                       V            T.sub.6 =0 0.1642F                                                                            ND(6) = 1.78833                                                                         ν(6) = 50.47                            R.sub.11 = -0.7506F                                                                            s.sub.6 = 0.7957                                             R.sub.12 = 2.2095F                                                                     T.sub.7 = 0.0821F                                                                             ND(7) = 1.78446                                                                         ν(7) = 25.75                        VI  R.sub.13 = 0.7295F                                                                     T.sub.8 = 0.1916F                                                                             ND(8) = 1.69669                                                                         ν(8) = 56.13                            R.sub.14 = -2.6553F                                                                            S.sub.7 = 0.0049F                                            R.sub.15 = 0.5296F                                                        VII          T.sub.9 = 0.1916F                                                                             ND(9) = 1.69669                                                                         ν(9) = 56.13                            R.sub.16 = 0.4342F                                                        __________________________________________________________________________

wherein axial thicknesses of successive lens elements are T5 to T9,successive axial spaces are S4 to S7, successive lens radii are R8 toR16, where - applies to surfaces whose center of curvature lies on theobject side of the vertices, refractive indices and Abbe numbers of thesuccessive lenses are ND(5) to ND(9), ν (5) to ν (9) respectively, and Fis the focal length of the objective in millimeters.
 8. The microscopeobjective of claim 7 wherein the focal length is 18.265.
 9. Themicroscope objective of claim 3 consisting of the defined lens elementshaving the following parameters:

    __________________________________________________________________________                                    Refractive                                                                              Abbe                                Lens                                                                              Radius    Thickness                                                                              Space    Index     Number                              __________________________________________________________________________                           S.sub.8  = 0.20151F                                        R.sub.17 = -0.27049F                                                      VIII          T.sub.9 = 0.27378F                                                                              ND(9)  = 1.78816                                                                        ν(9)  = 47.37                        R.sub.18 = -0.47856F                                                                             S.sub.9  = 0.00548F                                        R.sub.19 = -1.71598F                                                      IX            T.sub.10 = 0.16427F                                                                             ND(10) = 1.78816                                                                        ν(10) = 47.37                        R.sub.20 = -0.89799F                                                                             S.sub.10 = 0.25847F                                        R.sub.21 = 3.03510F                                                       X             T.sub.11 = 0.19164F                                                                             ND(11) = 1.78816                                                                        ν(11) = 47.37                        R.sub.22 = -7.39856F                                                                             S.sub.11 = 0.53892F                                        R.sub.23 = -4.65088F                                                                    T.sub.12 = 0.08213F                                                                             ND(12) = 1.80491                                                                        ν(12) = 25.42                    XI  R.sub.24 = 0.76274F                                                                     T.sub.13 = 0.19164F                                                                             ND(13) = 1.70166                                                                        ν(13) = 41.00                        R.sub.25 = -1.15457F                                                      __________________________________________________________________________

wherein axial thicknesses of successive lens elements are T9 to T13,successive axial spaces are S8 to S11, successive lens radii are R17 toR25 where - applies to surfaces whose center of curvature lies on theobject side of the vertices, refractive indices and Abbe numbers of thesuccessive lenses are ND(9) to ND(13), ν (9) to ν (13) respectively, andF is the focal length of the objective in millimeters.
 10. Themicroscope objective of claim 9 wherein F is 18.263.
 11. The microscopeobjective of claim 4 consisting of the defined elements having thefollowing parameters:

    __________________________________________________________________________                                    Refractive                                                                              Abbe                                Lens                                                                                Radius  Thickness                                                                              Space    Index     Number                              __________________________________________________________________________                           S.sub.12 = 0.40735F                                        R.sub.26 = -0.32605F                                                      XII           T.sub.14 = 0.26827F                                                                             ND(14)= 1.78816                                                                         ν(14) = 47.37                        R.sub.27 = -0.53042F                                                                             S.sub.13 = 0.00537F                                        R.sub.28 = -2.16525F                                                      XIII          T.sub.15 = 0.16096F                                                                             ND(15) = 1.78816                                                                        ν(15) = 47.37                        R.sub.29 = -0.99163F                                                                             S.sub.14 = 0.12438F                                        R.sub.30 = 1.73624F                                                       XIV           T.sub.16 = 0.18779F                                                                             ND(16) = 1.78816                                                                        ν(16) = 47.37                        R.sub.31 = 12.952F                                                                               S.sub.15 = 0.41384F                                        R.sub.32 = 12.952F                                                                      T.sub.17 = 0.08048F                                                                             ND(17) = 1.80491                                                                        ν(17) = 25.42                    XV  R.sub.33 = 0.79515F                                                                     T.sub.18 = 0.18779F                                                                             ND(18) = 1.52249                                                                        ν(18) = 60.13                        R.sub.34 = -1.4003F                                                       __________________________________________________________________________

wherein axial thicknesses of successive lens elements are T14 to T18,successive axial spaces are S12 to S15, successive lens radii are R26 toR34 where - applies to surfaces whose center of curvature lies on theobject side of the vertices, refractive indices and Abbe numbers of thesuccessive lenses are ND(14) to ND(18), ν (14) to ν (18) respectively,and F is the objective focal length in millimeters.
 12. The microscopeobjective of claim 11 wherein F is 18.638.